Reproductive failures and explosive population growth rates are two important health and economic problems affecting every sector of our society. Their successful solution depends, in part, upon a more perfect understanding of the control mechanisms which are operative in reproduction. Our general aim is to increase our understanding of how the ovarian steroids interact with reproductive tract tissue to control their morphological and biochemical state. Our studies will be conducted on oviducts obtained from women at all reproductive stages and those taking oral contraceptives, and on oviducts and uteri obtained from either intact cats or those which have been ovariectomized and subsequently treated with various regimens of estradiol and/or progesterone. Estradiol and progesterone will be quantified using an exchange assay technique. These data will be correlated with tissue morphology as determined by light and electron microscopy of the mucosa of the oviduct and the endometrium of the uterus. A further objective is to determine if progesterone administration causes release of a specific protein into the lumen. For this purpose uterine flushings obtained before and after progesterone treatment will be analyzed by SDS gel electrophoresis. These data will be correlated with the morphology of the glandular epithelium. We hope to be able to identify specific proteins in uterine fluid and to determine which steroids control their synthesis and release. These studies will provide important morphological, endocrinological and biochemical data on the effects of the ovarian steroids in reproductive tract tissue.